| Japanese Journal of Clinical Oncology | Pages |
Introduction
Case Report
Discussion
Acknowledgments
References
Localized Muscular Mucormycosis in a Child with Acute Leukemia
INTRODUCTION
Mucormycosis is a rare suppurative mycotic infection caused by certain genera of the class Zygomycetes, order Mucorales. Mucorales are usually not pathogenic in the normal host, but cause opportunistic infection in patients with diabetes, leukemia, lymphoma and other malignancies. Patients with burns, organ transplantation or prolonged immunosuppressive therapy are also susceptible. Intravenous drug users are also at risk of acquiring the disease.
Mucormycosis is characterized by vascular invasion and intravascular thromboses accompanied by intense suppuration and the production of black necrotic pus. Untreated cases progress rapidly and often end in death. We describe a child with acute leukemia who developed mucormycosis limited to the muscle of the lower extremity and was treated successfully with early debridement and systemic administration of amphotericin-B.
CASE REPORT
A 9-year-old Korean boy was diagnosed as having biphenotypic acute leukemia at Dong San Medical Center, Keimyung University, Taegu, Korea. The patient had a history of intermittent fever and proptosis for 3 weeks prior to admission. On admission he had shown generalized weakness, bilateral proptosis, mild hepatosplenomegaly and cervical lymphadenopathy on physical examination. The total white cell count was 63 900/[mu]l with 4% neutrophils, 4% lymphocytes, 4% monocytes, 6% myelocytes and 82% blast forms and the hemoglobin level was 8.4 gm/dl with 100 × 103/[mu]l platelets. A bone marrow aspiration specimen contained 90.4% undifferentiated blasts, representing two separate populations of neoplastic cells with different lineage expression and showing positive periodic acid-Schiff (PAS) and peroxidase (POD) staining. The immunophenotype was B-lymphoid with myeloid lineage-positive cells. The patient was given cytosine arabinoside and idarubicin as an induction regimen, according to the Korean Society of Pediatric Hematology/Oncology protocol. Ten days after initiation of chemotherapy he developed a fever of 39-40oC. The following day, he complained of pain in his left thigh just above the knee, when the total white cell count was 400/[mu]l. The lesion was tender, but no swelling was seen.
The regional lymph nodes were not enlarged. There was no history of intramuscular or subcutaneous injection in this region and there were no symptoms or signs referable to respiratory or sinus infections.
Ultrasonography of the affected region of the extremity revealed an ill-defined echogenic mass involving the left vastus intermedius muscle with a low echogenic focus at the center, suggestive of myositis (Fig. 1 ). Magnetic resonance imaging also showed an ill-defined enhanced mass on the T1-weighted image and a round high-signal-intensity area on the T2-weighted image, suggesting a hemorrhagic lesion in the vastus intermedius (Fig. 2 ). An excisional biopsy was carried out, which revealed thickened muscle and periosteum containing inflamed and necrotic tissue (Fig. 3 ). The gross specimen consisted of multiple pieces of pale gray soft tissue in aggregates, and a section of this specimen showed a round cystic space with an inner wall covered with yellowish-brown necrotic debris and a brownish ovoid ball measuring 1.0 × 0.8 × 0.5 cm in the cystic space (Fig. 4 ). Microscopically, the brownish ovoid ball contained many irregularly branching non-septate hyphae intermixed with necrotic muscle fibers and neutrophil infiltrates (Fig. 5 ). A histologic diagnosis of mucormycosis was made, but fungal cultures of the biopsy material, blood and urine were all negative. The lesion was debrided and the patient was started on amphotericin-B postoperatively, to a total dose of 1.02 over 6 weeks.
DISCUSSION
The class Zygomycetes consists of two orders, the Mucorales and Entomophthorales. The hyphae of mucorales are characteristically large, and often twisted or ribbon-like, and are unique among pathogenic fungi in having no septa. Mucormycosis may be subdivided into several distinct clinical forms depending on the site of involvement: rhinocerebral, pulmonary, gastrointestinal, cutaneous, disseminated and other rare forms (1 ). In Korea, rhinocerebral, cutaneous, pulmonary, renal and endocardial as well as disseminated forms of mucormycosis have been reported. Among these, cases of the rhinocerebral form are most common, as in other countries (2 ,3 ). Involvement of muscle in cases of disseminated mucormycosis has been reported (4 ) but cases in which muscle is the initial or only site of infection are extremely rare. No cases of muscular mucormycosis in large series of more than 75 cases (5 -7 ) have been reported. In patients with leukemia or lymphoma, the most frequent site of involvement is the respiratory tract (5 ,8 ). However, in the present case there were no respiratory symptoms, and both sinus and chest X-rays showed a normal appearance. Our patient is the first child with leukemia reported to have developed mucormycosis as an isolated muscular lesion during the course of remission-induction therapy.
Mucormycosis is usually acquired by humans after inhalation of spores, and occasionally may result from cutaneous inoculation of spores at the site of trauma, burn or invasive procedures in immunocompromised hosts (1 ,9 ,10 ). In our patient, the route of infection was unknown; he had no history of injections or trauma in the affected region.
Acknowledgments
The authors are very grateful to Dr T. H. Ghim, Division of Pediatric Hematology/Oncology, Department of Pediatrics, Emory University, School of Medicine, for critically reviewing the manuscript and for helpful comments and suggestions.
References
This page is run by Oxford University Press, Great Clarendon Street, Oxford OX2 6DP, as part of the OUP Journals
Comments and feedback: www-admin{at}oup.co.uk
Last modification: 19 May 1998
Copyright© Japanese Journal of Clinical Oncology, 1997.
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||